1. Field of the Invention
This invention relates to a cooling system, and more particularly, it relates to a venturi used in a closed-loop cooling system to facilitate cooling a heat-generating component by raising the pressure of the fluid in the system and, therefore, the boiling point of the fluid, with the increased pressure establishing that there is flow in the closed-loop system.
2. Description of the Prior Art
In many prior art cooling systems, the fluid is absorbing heat from a heat-generating component. The fluid is conveyed to a heat exchanger which dissipates the heat and the fluid is then recirculated to the heat-generating component. The size of the heat exchanger is directly related to the amount of heat dissipation required. For example, in a typical X-ray system, an X-ray tube generates a tremendous amount of heat on the order of 1 KW to about 10 KW. The X-ray tube is typically cooled by a fluid that is pumped to a conventional heat exchanger where it is cooled and then pumped back to the heat-generating component.
In the past, if a flow rate of the fluid fell below a predetermined flow rate, the temperature of the fluid in the system would necessarily increase to the point where the fluid in the system would boil or until a limit control would turn the heat-generating component off. This boiling would sometimes cause cavitation in the pump.
The increase in temperature of the fluid could also result in the heat-generating component not being cooled to the desired level. This could either degrade or completely ruin the performance of the heat-generating component altogether.
In the typical system of the past, a flow switch was used to turn the system off when the flow rate of the fluid became too low. FIG. 6 is a schematic illustration of a venturi which will be used to describe a conventional manner of measuring the flow rate. Referring to FIG. 6, the velocity at point B is higher than at either of sections A, and the pressure (measured by the difference in level in the liquid in the two legs of the U-tube at B) is correspondingly greater.
Since the difference in pressure between B and A depends on the velocity, it must also depend on the quantity of fluid passing through the pipe per unit of time (flow rate in cubic feet/second equals cross-sectional area of pipe in ft2xc3x97the velocity in ft./second). Consequently, the pressure difference provided a measure for the flow rate. In the gradually tapered portion of the pipe downstream of B, the velocity of the fluid is reduced and the pressure in the pipe restored to the value it had before passing through the construction.
A pressure differential switch would be attached to the throat and an end of the venturi to generate a flow rate measurement. This measurement would then be used to start or shut the heat-generating component down.
In the past, a conventional pressure differential switch measured this pressure difference in order to provide a correlating measurement of the fluid flow rate in the system. The flow rate would then be used to control the operation of the heat-generating component, such as an X-ray tube.
Unfortunately, the pressure differential switch of the type used in these types of cooling systems of the past and described earlier herein are expensive and require additional care when coupling to the venturi. The pressure differential switches of the past were certainly more expensive than a conventional pressure switch which simply monitors a pressure at a given point in a conduit in the closed-loop system.
What is needed, therefore, is a system and method which facilitates using low-cost components, such as a non-differential pressure switch (rather than a differential pressure switch), which also provides a means for increasing pressure in the closed-loop system.
It is, therefore, a primary object of the invention to provide a system and method for improving cooling of a heat-generating component, such as an X-ray tube in an X-ray system.
Another object of the invention is to provide a closed-loop cooling system which uses a venturi and pressure switch combination, rather than a differential pressure switch, to facilitate controlling cooling of one or more components in the system.
Another object of the invention is to provide a closed-loop system having a venturi whose throat is set at a predetermined pressure, such as atmospheric pressure so that the venturi can provide means for controlling cooling of the heat-generating component in the system.
In one aspect, this invention comprises a method for increasing pressure in a closed-loop system comprising a pump for pumping fluid in the system, a heat-generating component and a heat-rejection component, the method comprising the steps of situating a venturi in series in the closed-loop system and providing a predetermined pressure at a throat of the venturi, using the pump to cause flow in the closed-loop system in order to increase pressure in the system, thereby increasing the boiling point of the fluid, the overall pressure being greater than the predetermined pressure.
In another aspect this invention comprises a cooling system for cooling a component comprising a heat-rejection component coupled to the component, a pump for pumping fluid to the heat-rejection component and the component, a conduit for communicating fluid among the component, the heat-rejection component and the pump, the conduit comprising a venturi having a predetermined pressure applied at a throat of the venturi.
In a yet another aspect, this invention comprises An X-ray system comprising an X-ray apparatus for generating X-rays, the X-ray apparatus comprising an X-ray tube situated in an X-ray tube casing and a cooling system for cooling the X-ray tube, the cooling system comprising a heat-rejection component coupled to the X-ray tube casing, a pump for pumping fluid to the heat-rejection component and the component, a conduit for communicating fluid among the X-ray tube casing, the heat-rejection component and the pump; the conduit comprising a venturi having a predetermined pressure applied at a throat of the venturi.
In yet another aspect, this invention comprises a method for cooling a component situated in a system, the method comprising the steps of providing a conduit coupled to the component, coupling the component casing to a pump for pumping a cooling fluid through the conduit and to a heat-rejection component, increasing a boiling point of the cooling fluid, thereby increasing an operating temperature of the X-ray system.
In still another aspect, this invention comprises a method for cooling a component situated in a system, the said method comprising the steps of providing a conduit coupled to the component, coupling the component casing to a pump for pumping a cooling fluid through the conduit and to a heat-rejection component, increasing a boiling point of the cooling fluid, thereby increasing an operating temperature of the X-ray system.
These and other objects and advantages of the invention will be apparent from the following description, the appended claims, and the accompanying drawings.